Timolol is a non-selective beta blocker licensed for the treatment of hypertension, angina, prophylactic treatment of migraine and to reduce mortality and reinfarction in patients surviving acute myocardial infarction. It is also used topically (ophthalmically) in open-angle glaucoma and ocular hypertension.
Data on timolol use in pregnancy are limited and relate primarily to topical use. Fetal bradycardia has been documented in a single case report with topical use but a causal association has not been proven and an evidence-based assessment of the potential risks of miscarriage, congenital malformation, stillbirth, intrauterine growth restriction (IUGR), preterm delivery and adverse neurodevelopmental effects following in utero exposure is not possible. However, when pregnancy is being considered, any theoretical risks to the fetus should be weighed against the potential adverse effects (including permanent loss of vision) for the mother from untreated glaucoma.
Use of beta blockers in pregnancy has been associated with adverse effects on fetal growth, although because maternal hypertension is linked to IUGR, analysis is complex and any contribution of beta blocker exposure to this outcome remains unquantified. Overall, data do not suggest that gestational beta blocker exposure increases the risk of preterm delivery. Data on rates of miscarriage, stillbirth and neurodevelopmental outcomes are too limited to permit a risk assessment.
Use of beta blockers near term may result in neonatal beta-adrenoceptor blockade, leading to neonatal bradycardia, hypotension and hypoglycaemia. Respiratory distress has also been reported. Assessment of the neonate for these effects is thus advised. Although no reports of neonatal hypotension or hypoglycaemia following topical use of timolol in pregnancy have been identified in the literature, theoretical concerns may exist. Assessment of the neonate for these effects is thus advised.
Exposure to timolol at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.
This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.
If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.
If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.